Assig-nob



M. F. H. GOUVERNEUR.

METHOD AND MEANS FOR FORMING PASSAGES IN PLASTIC MATERIAL.

APPLICATION FILED MAY 26. 1920.-

' 1,413,023. Patented pr-18,1922;

MINOR F. H. GOUVERNEUR, OF ROCHESTER, NEXV YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, TO LOCKE INSULATOR, CORPORATION, OF BALTIMORE, MARY- LAND, A CORPORATION OF MIARYLAND.

METHOD AND MEANS FOR FOR-MING RASSAGES IN PLASTIC MATERIAL.

Specification of Letters Patent,

Patented Apr. 18 1922.

Application filed May 26, 1920. Serial No. 384,388.

tion of the invention, such as will enable others skilled in the art to which it appertains to make and use the My invention relates to a method and means for forming passages or perforations in porcelain or other material which is similarly worked, shaped or manipulated while in a plastic state prior to being hardened by firing, drying or baking. The invention is especially adapted for the production of passages or perforations in electric insulators where it is desired to makethe passage {urn Iphrongh an angle in the course of its engt While attempts have been made by the casting process to form porcelain insulators with holes or passages to receive bolts, cables and the like for attaching metal parts to the porcelain, the results attained have not been sufficiently satisfactoryto lead to the commercial adoption of this process, and open ended passages in porcelain insulating bodies are, so far as I am aware, now universally made by drilling the material after it has been hardened by firing. By my method the passage is formed in the plastic material be fore it is fired by cutting therefrom a core the shape of the passage,the core being subject to no substantial displacement with respect to the body of plastic material while it is being cut and-being removed'after having been completely formed. In this way the passage is produced with a minimum disturbance of the plastic porcelain, the result being that the walls of the'passage are smooth and upon firing do'notdevelop cracks weakening the insulator both physically and in respect to its electrical resistance.

In practicing my method I prefer to employ a hollow cutter formed as a thin narrow ring-like blade or band, and I have illustrated such a cutter as constituting part of a tool suitable for practicing the invention;

but it is to be understood that the special de sign oftool shown and described is merely illustrative of an appliance suitable for use in performing the method.

In the drawings which illustrate two slightly different forms of tools and the manner of their use to cut arcuate passages through plastic bodies:-

Figure 1 is a perspective view of a tool for cutting a curvilinear passage from one side to the opposite side of a wall of plastic ma terial.

Fig. 2 shows such a tool as applied to the plastic material ready to be actuated. to cut the passage therein, the form of the passage being indicated by dotted lines.

Fig. 3 is a view corresponding to Fig. 2 but illustrating the position of the tool at the end. of its cutting operation.

Fig. 4 is an enlarged detail view showing the tool in section and illustrating the man ner of withdrawing the core from the passage which has been cut.

Fig. 5 is a detail perspective view illustrating the use of the tool shown in Fig. 1 in conjunction with a template applied to the plastic body for guiding the tool during its cutting operation.

Fig. 6 is a view of u modified tool espe' cially suitable for cutting circular passage beneath a projection on the body of plastic material, the course of the passage being indicated by dotted lines.

F ig. 7 is a detail sectional view of the cutting end of the tool illustrated in Figs. 1 to 5. inclusive.

The cutting tool which is illustrated in Figs. 1 to 55, inclusive. is designed to form a passage of circular cross section through a wall of plastic material having parallel faces. It involves an arcuate circularly curved stem. 1 to one end of which is rigidly attached an operating handle 2. The handle 2 is preferably substantially radial to the curved stem 1 as such an arrangement facilitates the manipulation of the tool in causing its cutter to follow a circular path; and such a disposition of the handle is also advantageous in case, as illustrated in Fig. 6, the passage to be cut enters and leaves surfaces which are in the same plane. The end of the stem 1 opposite the handle corresponding surfaces oi? the cutter o bears a hollow cutter 3 having a closed periphery, said cutter being formed as a thin narrow blade having a cutting edge 4 e:-:- tending completely around its circuzn'ter; once. The curvilinear stem 1 is of: channel form, its inner and outer faces being parallel and corresponding to the contour of the walls of the channel to be cut. and the respectively merge into and form continuations of? the adjacent surfaces of the stern to which the cutter is attached at one side only. 7

here the passage to be cut througjgh a wall ha ing parallel faces, shown in l i 2, 3, 4E and 5, the leading or cutting edge 4-. of the cutter is arranged in a plane which is offset from or passes to one side of the center of curvature of the stem 1 so (see Fig. 3) the entire cutting edge l; 'Wlll coincidently merge from the plastic muterial at the end of the cutting opei t This prevents rupturing or tearing or walls of the passage.

The cutting edge t is formed by bevclinzr the hollow cutter 8 on the inside as ind cated at 5 in Fig. 7, thus making the diameter oi? the passage equal to the exterior diameter of the cutter and thereby permitting the cutter and stem 1 readily to move through the plastic mass as the cutting pro ceeds without binding upon the plastic material forming the walls ot the passage. The opening through the hollow cutter 3 is somewhat constricted back of its cutting edge by inclining the portion 6 of the blade in Wardly to a slight extent. Since the core cut from the plastic material by the tool is compressed as the cutter moves forwa rd and as it subsequently expands somewhat back of the hollow cutter as the cutter advances, this constriction of the opening through the cutter causes the portion 6 ot the latter to bite into the core (see Fig. 41:) when the tool is manipulated to withdraw the cutter trom the passage, the core thereby being extracted by the tool after being completely cut.

As shown in'Figs. 2, 3, 4i and 6, the plastic material itself may be provided with a face or surface 7 in the nature of atemplate assistmg in guiding the movement of the tool; but, as shown in Fig. 5, iii? the surface oi the plastic body through which the passage is to be formed does not lend itself to such purpose, a template 8 of the desired charshown in Fig. 5 is one which may be used in forming radially disposed curvilinear passages through a hollow cylinderypairs of flanges 9 which receive the tool between them regulating the spacingof the passages.

The tool illustrated in Fig. 6 is identical with that heretofore described except that the leading or cutting edge 10 of the hollow cutter 11 is in a plane which is approximately radial to the curved stem 1. This form oi? tool is also provided with a substantially radially extending handle The manner of cutting and withdrawing the core from the plastic body by theuse of the cutting tool which has been described will be readily understood upon reference to Figs. 2 3 and t oi? the drawings-s, Fig. 2 illustrating the tool ready to begin the cut ting, Fig. 3 illustrating position at the end of the cutting operation, and Fig. l showing the operation of withdrawing the core from the plastic body.

I claim l. The method of producing a curvilinear passage in an article formed from plastic material and subsequently hardened, which consists in cutting a core the shape of the L 5e from the material while in the plassta'te without substantially displacing said core with respect to the body of plasti* material and subserpiently removing said core prior to said hardening of the plastic material.

The method of forming in plastic maiial a passage whose direction changes between its ends, which involves linearly moving without peripheral rotation a hollow peripherally closed cutter through thefplastic material and simultaneouslycausing the leading edge of said cutter to be presented at successively different angles to the plastic material to be cut and subsequently removing the material cut by the cutter. V

3. The method of forming in plastic material a passage whose direction changes between its ends which involves curvilinearly moving without peripheral rotation a. hollow cutter through the. plastic material to cut a core therefrom, retracting the cutter on the core for a portion of the'length ot the core, and thereafter simultaneously withdrawing said cutter and core from the plastic material.

l. The method of "forming in porcelain a passage waose direction changes between its endawhich involves curvilinearly moving without peripheral. rotation a hollow ring- A. cutting tool provided atone end witi a hollow cutter having a closed periphery and provided at the other endwith a handle and having an intermediate arcuate portion.connecting said cutter and handle and offset from said handle.

6. A cutting tool having a curvilinear stemand provided atone end of said stem with a hollow cutter having a closed periphery. V

7. Acutting tool provided witha hollow cutter having a closed periphery, a handle,

and an intermediate arcuate portion connecting said cutter and handle, said handle adjacent said intermediate arcuate portion being substantially radial to said arcuate portion.

8. A cutting tool having a. curvilinear stem of channel form and orovided at one end of said stem with a hollow cutter having a closed periphery,

A cutting tool having a curvilinear stem of channel form and provided at one end of said stem with a hollow cutter having a closed. periphery, the exterior and interior surfaces of said cutter respectively merging into correspoiulingly formed surlfnces of, said curvilinear stem.

10. A cutting tool. having a curvilinear stem and provided at one end of said stem with a hollow cutter having a closed periphery, the opening through said cutter being constricted back of its cutting edge.

ii. A cutting tool having a curved stein provided at one end with a hollow cutter having a closed periphery, said cutter being beveled. on the interior to form the cutting edge.

12., A. cutting tool having a uniformly curved stem and provided at one end of said stem with a hollow cutter having a closed periphei v the opening tl'irough said cutter being constricted hack of its cutting edge and said stem. being connected to said. outter at one side only.

13. A cutting tool having a stem termed as a circular arc and provided at one end of said stem with a hollow cutter having a closed periphery, the cutting edge of said cutter being in a plane oli'set from the center of curvature of said stem.

14. A cutting tool provided with a hollow cutter having a cutting edge coextensive with its circumference and provided with a stem whose inner surface struck from the same radius as the said cutting edge rigidly secured to said cutter, a portion of. said cutter being oflset from said stem.

15. A cutting tool for perforating a plastic mass, said. tool comprising a hollow cutter formed of a narrow blade having a cutting ed e extending entirel around its circumterence and a curved stem eccentrically disposed with respect to said cutter for forcing said blade into and through the plastic mass in a curvilinear direction,

In testimony whereof I afiix my signature.

MINOR F. H. GOUVERNEUR. 

